Many games these days are touted as being 'sandboxes'. This refers to the idea that you can enter the pre-designed world and do whatever you want- you want to smack a grandma in the face? Go ahead. Most of these do not allow you full control over the VR presented, however; but offerer variations on a theme.
Take the most recent high profile entry in the sandbox genre, 'Grand Theft Auto IV.' Rather than letting you do whatever you want, you're given New York. And I mean New York. Five burghs. Manhattan, Jersey, Bronx, etc. All there to run around in. The name of the game is detail; so much so that most of my jollies were pulled from just seeing what they included next. If you get in a car, the cabin lights turn on, then turn off when you close the door. They included a fake interweb with almost a 1000 different pages to visit. You can buy ringtones on the fake internet then download the fake ringtone to your fake phone in-game.
Mercenaries 2: World in Flames, is quite the opposite. Let me liken it to a friend
of mine, who will go nameless. Let's just say she's a soprano grad student at my college. And she was in Hotel Casablanca. And she plays World of Warcraft. Her enemy is subtlety. If I am the refined plot and attention to detail of GTAIV, she is M2. Meaning: 'SPLOSIONS.
Mercenaries 2, henceforth referred to as M2, features 3 mercenaries (clearly) traveling through venezuela, working for various political factions, all in the name of blowing the shit out of everything.
(The Merc 2 team (of 3))
Now, I only rented the game, so I can not claim to have plumbed the game's fiery depths, but I will say that as far as blowing stuff up goes, this is the game to beat. Instead of giving a thoughtful analysis, I'll just tell you how about 15 minutes of one of my playthroughs went.
(Keep in mind that there were 0 load times in the following)
I started a mission that required me to fetch a military grade bunker-buster bomb so I could get to some little bugger holed up on an island in the middle of a huge lake. So I leave my mansion (video games always give you mansions) and go down to a country road. I see a dude riding a motorcycle, so I politely rip him off of his bike and head north.
Now, the world map is probably 15x15 actual-game-miles wide, so it's a fairly long ride through the lush, jungle infested mountains. I stop by a small town that I see on my radar is holding some C4 charges (which I steal). Once I reach the north coast, the henchmen of the terrorist guy spot me and start to chase me with tanks, helicopter, jeeps, etc.

(Not me playing, but I swear it looked like this)
A tank shell hits my motorcycle, sending my character ragdolling 200 ft. in the air. But this is alright as the bike is a bitch to drive in water. I stand up and hop onto a nearby jet ski. I take the jet ski further north , all the while being chased by a helicopter. Weaving through the wake, I spot the island with the bombs. I hit the beach, hop off the waverunner, and come under fire from a pill box. Oh? OH? I have this C4 here! BOOM. A tank? Oh??? I run up to the tank, jump onto its cannon, and drop a grenade into the driver's hatch, ruining his shit.
(from here the story is abridged due to a need to get onto WoW)
I eventually get the bombs, find the compound the terrorist is in, bypass the suggested route entirely (mainly because everything is destructible) by blowing up the walls of the compound, send in the bunker buster, and call it a day.
Wash, rinse, repeat.
If I had any quibbles, it would be that the driving physics leave much to be desired. GTA4 was the first game to give a legit. illusion of weight for vehicles, where as here you feel like you're driving in an ice storm.
Especially fun when played with a friend on LIVE.
(Oh yeah. You can eventually call in a tactical nuke.)